Curiosity is checking out banded terrain on Mars

NASA's Curiosity rover is spending sols 5010 to 5015 checking a subtly banded part of Mount Sharp, where small changes in sand, outcrop texture and rock chemistry can help the team decide what kind of Martian record it is driving across.

The Curiosity team said in a September 22 mission update that the rover is moving through the informally named Valle Grande after climbing over what the team interpreted as an erosional supersurface, a gap or boundary in the usual rock record. The new target zone contains bands about 25 to 200 meters wide, or roughly 80 to 650 feet, with darker sandier areas and rougher exposed rock.

What Curiosity is checking

The rover team is treating the bands as a field problem. Some areas look sandier from a distance because darker material covers more of the surface. Other areas show more continuous outcrop, which can reveal contacts between units. A contact is a boundary between different rock layers or surface materials. On Mars, that boundary can preserve a change in environment, erosion or deposition.

NASA says the rover found rough, often nodular bedrock surrounded by sand and coarse pebbly sand. Earlier in the plan, APXS and MAHLI investigated brushed nodular bedrock at Cerro Armazones and Monte Melimoyu. APXS measures elemental chemistry; MAHLI is a close-up camera used to inspect textures. ChemCam used laser-induced breakdown spectroscopy, which fires a laser at a small target and reads the resulting light, on dark nodules and float rocks.

The drive changed the target list

After a drive of about 60 meters, nearly 200 feet, the rover ended up with mostly sand nearby and one small rough-textured outcrop close enough for contact science and ChemCam work. That outcrop matters because NASA describes it as having small flakes, chips and laminated areas. Laminated rock can point to layered material, while the chemistry and texture help decide whether a band is a real geologic unit or mainly a surface expression shaped by sand cover.

The plan now sends the rover's instruments to specific targets:

• MAHLI imaging of rougher textures at Yungay and Chiu Chiu.
• APXS chemistry on Chiu Chiu.
• ChemCam LIBS on Puya Raimondii and a smoother area named Liolaemus Tacnae.
• Mastcam and ChemCam mosaics of nearby buttes and the Sullivan Field sand field.

Why it matters for the mission

Curiosity's larger job is to read Mount Sharp as a stack of environmental records. A banded zone is useful only if the team can connect what it sees from a distance to what the instruments measure up close. That is why the plan mixes contact science, laser chemistry, wide mosaics and environmental monitoring.

The distinction is practical. A darker stripe in an orbital or rover image may be a real change in rock, or it may be a layer partly hidden by loose sand. By brushing targets, checking chemistry and comparing close-up textures with wider mosaics, the team can avoid overreading a visual pattern before the rover has measured it.

The update is also a reminder that rover progress is not only about distance. A 60-meter drive can turn a broad science plan into a practical question: which rocks are close enough, safe enough and informative enough to measure before the rover moves again?

NASA says Navcam and Mastcam imaged the path ahead in the drive direction, where the subtle bands can be picked out by tonal differences. The next useful result is not a single dramatic discovery claim. It is whether the rover can tie those tonal bands to measurable changes in texture and chemistry as it gets closer.

Sources

• NASA: Curiosity Blog, Sols 5010-5015: Checking out the Bands
• NASA Curiosity mission page
• NASA Images and Media Guidelines